humanity and science in perspective cc105 prof. jackson
TRANSCRIPT
Humanity and Science in Perspective
CC105
Prof. Jackson
Today’s Music
“The Universe Song” Monty Python
Today’s Lecture
• The story of everything• Math in Nature• The cosmic size-scale• The cosmic time-scale• Science and truth• Humans• The future
What is Science?
“Science is the marriage of skepticism and wonder.”
Carl Sagan
The Story of Everything
• In the beginning…Big Bang, and there was light.
• Primordial soup spawns particles, and eventually hydrogen and helium.
• Stars form from the hydrogen/helium gas.
• Stars make heavy elements and explode.• More stars form, enriched with heavy
elements.• The Sun forms• The Earth forms as a byproduct• Chemistry on earth spawns life• Humans evolve from ancient ancestors.
“It is Nature herself, and not the mathematician, who brings mathematics into natural philosophy.”
Kant
Math in Nature
• Does math form the fundamental basis for everything?
• Math revealed in nature– LAWS– FORMS
SymmetryIn mathematics, “symmetry’’ refers to an operation that leaves an object unchanged.
Reflect through a mirror
Rotate by 90o
Crystals
Ice: hexagonal symmetry
Ice
Edward
Weston
What about life?
• Many creatures have mathematical shapes
• Many creatures exhibit symmetries– Bilateral– Rotational
Mathematical Forms in Life
Equiangular Spiral
0/0eRR
Edward WestonThe Chambered Nautilus
Nautilus Shell
A perfect logarithmic spiral!
More Equiangular Spirals
More spirals
Bilateral Symmetry
Bilaterally Symmetric Life
Bilaterally Symmetric Life
Edward Weston
Bilaterally Symmetric Life
Edward Weston
Bilaterally Symmetric Life
Edward
Weston
Rotational Symmetry
Rotationally Symmetric Life
Rotationally Symmetric Life
Rotationally Symmetric Life
Rotationally Symmetric Life
Rotationally Symmetric Life
Mushroom Gills
Mushrooms
Gill spacing never
too large
Fractals in nature
• Fractals are objects that look the same regardless of the magnification.
• “Scale-invariant”
Fractals
River drainage
More fractals
More fractals
More fractals
More fractals
Fractal Life
Fractal Life
Fractal Life
Fractal Life
Fractal Life
Fractal Life
Examples of fractals in nature
• Trees• Lungs• Viscous fingers (fluid flow)• Rain clouds• Electrical discharges• Shorelines
Fractals in music: Music is pink noise
Am
plit
ude
Frequency
White noiseAf
Pink noiseAf-1
Brown noiseAf-2
Mathematics is relevant
It is everywhere, and part of everything, both inanimate and animate.
The Cosmic Perspective
• Where do humans fit in?• Size• Time
The Cosmic Size Scale
Movie: Powers of Ten
The Cosmic Time Scale
• The Universe began about 14 billion years ago.
• The solar system formed about 5 billion years ago.
• Life appeared 3 billion years ago.• Homo sapiens appeared 100,000
years ago.
The Cosmic Time Line
15 billion yr 10 billion yr 5 billion yr today
Universe begins Solar system forms
5 billion yr 4 billion yr 3 billion yr 2 billion yr 1 billion yr
Earth forms Life begins Trilobites
today
The Cosmic Time Line
15 billion yr 10 billion yr 5 billion yr today
Universe begins Solar system forms
500 million yr 300 million yr 100 million yr
Trilobites Fishes Amphibians Reptiles Mammals Hominids
If Eternity Were A Year: Compress 14 billion years into one
Sun forms: Late AugustEarth forms: September 1Life begins: Late SeptemberLand animals: December 20Dinosaurs: December 29Hominids: 10:00 pm, December 31Homo sapiens: 11:53 pm December 31
“It is more important to have beauty in one’s equations than to have them fit experiments.”
Paul Dirac
Science and beauty
• Why does aesthetics play such an important role in science?
• Perhaps our notions of “beauty” reflect a concordance with the underlying mathematical structure of Nature.
• Is beauty truth? Or is truth beautiful?
The Faith behind Science
• The Universe is built on a foundation of order.
• The Universe is explicable.• The Universe is mathematical.• Nature operates with a few simple
laws.• These laws have the same rules
everywhere.
Science and truth
Science is only as good as its predictions!
Important to distinguish between the ideas and the predictions.
Science provides a quantitative description of Nature.
Can only describe reality within the limits of the human mind.
Science may never arrive at truth.
And yet…
Some ideas work so well they seem indistinguishable from truth:– Atoms– Gravity
Why does it work?
• Empiricism: go to Nature for answers
• Reject bad theories.
“The great tragedy of Nature is the murder of beautiful theories by ugly fact.” Mark Twain
Questions science cannot (yet) answer
• Is there existence after death?• What is reality?• Why is there something rather
than nothing?• What defines good and evil?
Science and religion and philosophy
Science seems to be encroaching on themes formerly addressed by philosophy and religion
• Creation• The nature of reality• The origin of humans• Our place in the Cosmos• The mind
Where Do Humans fit it?
The Copernican PrincipleHumans do not occupy any special place in the Universe.
We inhabit
• An ordinary planet• Orbiting an ordinary star• In the backwaters of the Milky Way• An ordinary galaxy• In an ordinary group of galaxies• In an ordinary super-cluster of
galaxies
Are we insignificant?
• Individually, perhaps• BUT… will humans colonize the stars?• Will we exploit the Galaxy’s
resources?• The role of the observer in quantum
mechanics• Does human thought collapse the
wave function?• We are part of the strange loop of
Nature.
The Future
• We face a catastrophe (war, plague, starvation).
• We learn to live in harmony with our planet.
• We move into space and colonize the Galaxy.
Are humans alone?
• Nothing particularly special about Earth
• Life may well exist on other planets• If their civilization got a head start,
they may well have already colonized the Milky Way
• If so, where are they?• We are looking!
Why are you here?
• Science is a key part of society.• Stimulates technology.• Provides the crucial knowledge for
social and ethical decisions.• Humans are a curious species, and
science provides answers.
Scientific Social Issues
• Extermination of species• Organ transplants• Cloning• Nuclear power and weapons• Overpopulation• Use of outer space• Global warming• Ozone depletion
Where do you find science?
Just open your eyes, and look around.